I recently came into a very large mp3 collection, ~50k songs, and need some tools to assist in cleaning it up.

Ive already gotten the folder structure cleaned up so that it in an Artist/Album/track#_title.mp3 format but the tags are an absolute mess. For example there are 500+ Rolling Stones tunes and they probably have 15 different genres. Ive got 2-3k songs that don't have albums in the tags. 2 or 3 spellings of Tom Waits. You get the picture...

Basically I need a recommendation for a tag clean up tool.

Beyond that any type of bulk normalization tool would be great as well.

Get MediaMonkey. It will do filename renaming easy and you can set up variables to pull in tags with it. It's also easy to fix tags, select whole album and change tags, etc. It's a library too. Also works well on synching to mp3 players too.